What it means
The supply voltage feeding injector group C has dropped below the lower limit. The injectors in this group lose drive voltage and may stop firing, so the cylinders they serve run lean or cut out. Causes: a blown fuse, a failed injector supply relay, a voltage drop in the supply harness, or a poor ground or connector on the group-C supply.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Injector group C uses a shared power supply so its injectors can open when commanded by the engine control module. This code sets when the module sees group C supply voltage below its expected lower limit, potentially leaving those injectors unable to deliver fuel consistently.
Common causes
Most likely first.
- Fuse, relay, or wiring fault on supply
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Misfire or rough idle on the affected cylinder
- Increased fuel consumption
- Possible fuel smell or smoke from exhaust
How to diagnose it
- Record freeze-frame data and check live misfire counts to identify when the group C low-voltage fault occurs and which cylinders are affected.
- Inspect the group C fuse, supply relay, connectors, and harness for corrosion, loose pins, a blown fuse, or chafed insulation.
- Measure voltage at the group C supply while the fault is present and compare it with the manufacturer's specification.
- Perform a loaded voltage-drop check along the group C supply path to locate resistance at a wire or connector.
- If the wiring and connections pass, test the supply relay and its control circuit using the vehicle's service information.
Common fixes
- Clean and secure corroded or loose group C supply connector pins.
- Repair damaged or high-resistance wiring in the group C supply harness.
- Replace a blown fuse after correcting the underlying cause.
- Replace a failed injector supply relay.
Can I keep driving?
Avoid driving if the engine is misfiring badly or running roughly, because unburned fuel can damage the catalytic converter. If it runs smoothly, keep trips short and have the group C supply checked promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.